Use TRYCATCH_FOR_V8STRINGRESOURCE in AbstractEventListener::invokeEventHandler()

Use TRYCATCH_FOR_V8STRINGRESOURCE in AbstractEventListener::invokeEventHandler() instead
of toWebCoreString() so that exceptions raised by ToString() are no longer ignored.
This affects the string returned by the onbeforeunload callback.

R=haraken
BUG=

Review URL: https://chromiumcodereview.appspot.com/23600034

git-svn-id: svn://svn.chromium.org/blink/trunk@157673 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix r157217, committed patch set didn't contain the latest review modifications.

BUG=

Review URL: https://chromiumcodereview.appspot.com/24119002

git-svn-id: svn://svn.chromium.org/blink/trunk@157674 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Pass isolate to v8::False() / v8::True() when possible

Pass isolate to v8::False() / v8::True() when possible to avoid implicit call to
v8::Isolate::GetCurrent().

R=haraken
BUG=

Review URL: https://chromiumcodereview.appspot.com/23619034

git-svn-id: svn://svn.chromium.org/blink/trunk@157675 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Rename FontLoader to FontFaceSet and Document.fontloader to Document.fonts.

This is the first step to support the new Promise-based draft spec.
http://dev.w3.org/csswg/css-font-load-events/

BUG=53213

Review URL: https://chromiumcodereview.appspot.com/23620044

git-svn-id: svn://svn.chromium.org/blink/trunk@157676 bbb929c8-8fbe-4397-9dbb-9b2b20218538